Silicon carbide semiconductor device

Abstract

A silicon carbide semiconductor device includes a silicon carbide substrate having a first main surface; a first electrode formed on the first main surface; and a plating film formed on the first electrode, wherein a first irregularity is formed on a surface of the plating film, and H1/H2 is 0.10 or less, where H1 is a difference between a maximum value of a distance to a top of the first irregularity from the first main surface and a minimum value of a distance to a bottom of the first irregularity from the first main surface, and H2 is a minimum value of a thickness of the plating film.

1 . A silicon carbide semiconductor device comprising:
 a silicon carbide substrate having a first main surface;   a first electrode formed on the first main surface; and   a plating film formed on the first electrode,   wherein a first irregularity is formed on a surface of the plating film, and H1/H2 is 0.10 or less, where H1 is a difference between a maximum value of a distance to a top of the first irregularity from the first main surface and a minimum value of a distance to a bottom of the first irregularity from the first main surface, and H2 is a minimum value of a thickness of the plating film.   
     
     
         2 . The silicon carbide semiconductor device as claimed in  claim 1 , wherein a second irregularity is formed on a surface of the first electrode, and H3/H4 is 0.30 or greater and 0.80 or less, where H3 is a difference between a maximum value of a distance to a top of the second irregularity from the first main surface and a minimum value of a distance to a bottom of the second irregularity from the first main surface, and H4 is a minimum value of a thickness of the first electrode. 
     
     
         3 . The silicon carbide semiconductor device as claimed in  claim 1 , wherein H1/H2 is 0.01 or greater and 0.10 or less. 
     
     
         4 . The silicon carbide semiconductor device as claimed in  claim 1 , wherein the first electrode contains aluminum or an aluminum alloy. 
     
     
         5 . The silicon carbide semiconductor device as claimed in  claim 1 , wherein the plating film includes a nickel plating film. 
     
     
         6 . The silicon carbide semiconductor device as claimed in  claim 5 , wherein an average crystal grain size at a surface of the nickel plating film is 1.0 μm or greater and 20.0 μm or less. 
     
     
         7 . The silicon carbide semiconductor device as claimed in  claim 5 , wherein the plating film further includes either a gold plating film or a silver plating film formed on or above the nickel plating film. 
     
     
         8 . The silicon carbide semiconductor device as claimed in  claim 7 , wherein the plating film further includes a palladium plating film that is formed between the nickel plating film and either the gold plating film or the silver plating film. 
     
     
         9 . The silicon carbide semiconductor device as claimed in  claim 1 , wherein the plating film includes a copper plating film. 
     
     
         10 . The silicon carbide semiconductor device as claimed in  claim 9 , wherein an average crystal grain size at a surface of the copper plating film is 1.0 μm or greater and 20.0 μm or less. 
     
     
         11 . The silicon carbide semiconductor device as claimed in  claim 9 , wherein the plating film further includes a tantalum nitride film or a titanium nitride film formed between the first electrode and the copper plating film. 
     
     
         12 . The silicon carbide semiconductor device as claimed in  claim 1 , further comprising a second electrode formed on the first main surface; and an insulating film that covers the second electrode, wherein the first electrode covers the insulating film.